Decorative sheet materials, and particularly resilient floor coverings, have been manufactured for many years and are customarily provided with surfaces having attractive patterns or designs printed thereon in various colors. However, after a period of time in use, these surface patterns or designs are worn away in places and the attractiveness of the variously colored surfaces is gradually diminished.
One method of avoiding, or at least postponing, the decreasing attractiveness of the variously colored patterns or designs, as they gradually wear in use, is to cover the surface of the decorative sheet material with a clear transparent coating or a wear layer which takes the brunt of the wear and is worn away gradually during the passage of time without affecting the attractiveness of the variously colored patterns or designs they protect. However, when the clear transparent coating or wear layer ultimately wears away, then the variously colored pattern or design begins to wear away and the attractiveness of the colored surface is diminished. Such methods are disclosed in many prior art patents, such as, for example, U.S. Pat. Nos. 3,293,094 and 3,293,108 to Nairn et al.
Another method of avoiding the decreasing attractiveness of the variously colored pattern or design is to have the various colorants penetrate deeply and completely through the decorative sheet material, so that, even as the surface of the decorative sheet material does wear away, the variously colored patterns or designs will not be visibly affected, insofar as an attractive appearance is concerned. Many methods have been devised in many efforts to achieve such desirable objects and purposes and are disclosed in many prior art patents, such as, for example, U.S. Pat. No. 3,276,904 to Palmer.
This is an excellent approach. However, such methods have not been completely successful or satisfactory and in many cases the various colors have migrated laterally or have bled and have run together. As a result, the variously colored patterns or designs have lost their sharpness of detail and have become undesirably blurred or indistinct.